Macular degeneration is the leading cause of vision loss in the United States of America. In macular degeneration, the central portion of the retina (a.k.a., the macula) deteriorates. When healthy, the macula collects and sends highly detailed images to the brain via the optic nerve. In early stages, macular degeneration typically does not significantly affect vision. If macular degeneration progresses beyond the early stages, vision becomes wavy and/or blurred. If macular degeneration continues to progress to advanced stages, central vision may be lost.
Although macular degeneration is currently considered to be incurable, treatments do exist that may slow the progression of the disease so as to prevent severe loss of vision. Treatment options include injection of an anti-angiogenic drug into the eye, laser therapy to destroy an actively growing abnormal blood vessel(s), and photodynamic laser therapy, which employs a light-sensitive drug to damage an abnormal blood vessel(s). Early detection of macular degeneration is of paramount importance in preventing advanced progression of macular degeneration prior to treatment to inhibit progression of the disease.
Early detection of macular degeneration can be accomplished using a suitable retinal imaging system. For example, Optical Coherence Tomography (OCT) is a non-invasive imaging technique relying on low coherence interferometry that can be used to generate a cross-sectional image of the macula. The cross-sectional view of the macula shows if the layers of the macula are distorted and can be used to monitor whether distortion of the layers of the macula has increased or decreased relative to an earlier cross-sectional image to assess the impact of treatment of the macular degeneration.
Existing OCT imaging systems, however, are typically expensive and may have to be operated by a trained technician. For example, a trained technician may be required to properly align an optical axis of the OCT imaging system with the optical axis of the eye examined. As a result, the use of such OCT imaging systems is typically restricted to specialized eye care clinics, thereby limiting use of such OCT imaging systems for widespread screening for early stage macular degeneration.